In recent years alternative network telephony, using at least in part a network other than the public switched telephone network (PSTN) to enable two or more parties to carry on a conversation in real time, has become increasingly popular. The advent of high-speed access to networks, such as the Internet, has further fueled this trend. Telephone functionality has been provided using personal computers (PC's) or computer workstations connected via the Internet and/or other networks, often through high-speed connections such as cable modems or digital subscriber line (DSL) connections. Telephone functionality has also been provided via cable television networks through television set top boxes equipped with cable modems, for example.
In many cases, a packet switched network protocol, such as the Internet protocol (IP), is used to provide alternative network telephony (e.g., IP telephony). Under such a protocol, the analog audio signal generated by a speaking call participant is digitized and sent via the alternative network from the sending station to the receiving station(s) in one or more data packets in accordance with the applicable protocol. At the receiving end, the data typically is reassembled, if necessary, and converted back to an analog audio signal. The data is then typically delivered to the recipient via an audio output device, such as one or more speakers, a headset, or a telephone handset or other output device.
It would be desirable for cable television service providers, providers of interactive television services and/or equipment, and/or other providers or potential providers of alternative network telephony equipment and services to have a way to compete effectively with more traditional providers of long distance and/or local telephone service. Such competition may bring lower prices, better and expanded service, and more choice to consumers.
One potential obstacle to such competition is the fact that the provision of telephone service is highly regulated. For example, regulations typically may require that telephone service meet certain standards of “permanence”—e.g., that basic telephone service continue to be available for a prolonged period of loss of electrical power at the site served, so that a consumer could make a telephone call to obtain essential emergency services or engage in other essential telephonic communication, during a loss of power. These standards may be difficult for alternative network telephony systems to meet, as such systems typically run on a computer, set top box, or other processing system that requires a source of electrical power. Providing an uninterruptible power supply (UPS) for such systems may be prohibitively expensive and otherwise impractical.
Therefore, there is a need for a way to provide telephone service to consumers of such services via alternative network telephony that enables such service to be provided in a reasonable and cost effective way during power outages and/or other times when the alternative network telephony service may not be available.